The Hybrid Automatic Repeat Request (HARQ) is a technology which makes a retransmission decision using the link level information. In the HARQ technology, the data receiver shall feed back to the data transmitter response information, which is one type of control information, so as to determine whether the data is correctly received. In the 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) system, the response information is mainly fed back to the base station through a Physical Uplink Control Channel (PUCCH) or a Physical Uplink Share Channel (PUSCH).
The 3GPP LTE system includes a Frequency Division Duplexing (FDD) system and a Time Division Duplexing (TDD) system. In which, the TDD system sends and receives the data in the same frequency channel but in different time, i.e., the data is sent and received using different time slots of the same frequency carrier. In addition, the TDD system supports different uplink-downlink configurations, and it can semi-statically adjust the uplink-downlink configuration according to different types of services, so as to meet the unsymmetrical uplink-downlink service requirements. Moreover, in correspondence with different uplink-downlink configurations, different timing relationships are set for feeding back the response information corresponding to the downlink transmission. Under various uplink-downlink configurations, the response information corresponding to the downlink transmission of one or more downlink subframes are fed back in corresponding uplink subframes, according to the timing relationships set for feeding back the response information corresponding to the downlink transmission.
In a system earlier than version LTE R11, the uplink-downlink configuration to be used is semi-statically set, and the set uplink-downlink configuration may be unmatched with the instantaneous service type, thus the resources cannot be effectively utilized. In order that the practically used uplink-downlink configuration is better matched with the instantaneous service type, and the communication resources are utilized more effectively, the dynamic TDD subframe application technology can be introduced into version LTE R11, i.e., the radio frame may be provided with some dynamic subframes serving as either the uplink subframes or the downlink subframes. FIG. 1 is a schematic diagram of an application of a dynamic TDD subframe in a radio frame, which illustrates that the last two subframes in every half radio frame are dynamic subframes.
During the implementation of the present disclosure, the inventor finds that in an application scenario of the dynamic TDD subframe, the dynamic subframe can be used in either the uplink transmission or downlink transmission, depending on the instantaneous service type, so the formed uplink-downlink configuration is variable. In addition, a signaling indicating whether the dynamic subframe is an uplink subframe or a downlink subframe may be lost or falsely detected by the User Equipment (UE). As a result, the base station and the UE may have inconsistent understandings of the formed uplink-downlink configuration. Thus, if the response information is fed back in real time according to the timing relationship corresponding to the formed uplink-downlink configuration, an erroneous transmission of the response information will occur, and the security of data transmission in the application scenario of the dynamic TDD subframe cannot be ensured. In addition, in the application scenario of the dynamic TDD subframe, sometimes the formed configuration even may not belong to any configuration in the existing LTE TDD system, thus there is no corresponding timing relationship for feeding back the response information. Therefore, how to feed back the response information in the application scenario of the dynamic TDD subframe is a problem emergently to be solved at present.